Quoting Daniele Ceraolo Spurio (2019-08-27 19:58:05) > The CS pre-parser can pre-fetch commands across memory sync points and > starting from gen12 it is able to pre-fetch across BB_START and BB_END > boundaries as well, so when we emit gpu relocs the pre-parser might > fetch the target location of the reloc before the memory write lands. > > The parser can't pre-fetch across the ctx switch, so we use a separate > context to guarantee that the memory is synchronized before the parser > can get to it. > > Note that there is no risk of the CS doing a lite restore from the reloc > context to the user context, even if the two have the same hw_id, > because since gen11 the CS also checks the LRCA when deciding if it can > lite-restore. > > v2: limit new context to gen12+, release in eb_destroy, add a comment > in emit_fini_breadcrumb (Chris). > > Suggested-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx> > Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Looks solid and the big explanatory reminders are very welcome. (I will shift it to gen11_fini_breadcrumbs I think, so it's closer to the gen12 divide.) Subtle changes in behaviour are easily forgotten. Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
